Estoril

The club was founded on 17 May 1939 as Grupo Desportivo Estoril Plage by, among others, Joaquim Cardim, José Ereia, João Rebelo, Armando Vilar, Ernesto Tomás, and Joaquim Nunes. The club's principal promoter was Fausto Cardoso de Figueiredo, the wealthy owner of the Lisbon-Cascais railway, the English hotels of the city, Paris and the Palace, the bath building, and the Estoril Casino. The team's badge and kit colours were inspired by Estoril's many beaches, considered the best in all of Portugal. The yellow symbolizes the colour of the sun, while the blue symbolizes the colour of the neighbouring Atlantic Ocean.

When the club was initially established it began to play in the Campeonato de Lisboa which was a league competition contested by teams from Lisbon. It also began to compete in the Taça de Portugal. Four years after its establishment, the club has reached the Taça de Portugal final in the 1943–44 season in which they lost to Benfica 8–0 at the Campo das Salésias in Lisbon.

Following that season the club reached for the Primeira Liga in the 1944–45 season where they finished seventh in their very first season in Portugal's top flight division. The next season saw the club play in the 1945–46 Segunda Divisão and the 1945–46 Campeonato de Lisboa. The club remained in the top flight until the 1952–53 Primeira Divisão season where they finished last and were relegated to the Portuguese Second Division.

The next season saw them begin their football life in the Segunda Divisão. Estoril played in the division for 22 years before gaining promotion to the top flight again. Following the appointment of experienced English manager Jimmy Hagan in 1973 who prior to being appointed as manager of Estoril had managed Benfica to three consecutive league titles in 1970–71, 1971–72 and 1972–73 as well as a Taça de Portugal in the 1971–72 season he helped the club achieve promotion to Primeira Liga. The club's return saw them finish an impressive eighth place in the league as well as a quarter-finalist in the cup competition. The next ten years saw the club remain in a stable position finishing in mid-table positions up until the mid-1980s.

In the late 1980s, the club appointed Fernando Santos as manager. A young coach who had played for the club during his professional career in the 1970s who had retired due to several injuries. He helped the club rebuild itself and improve its players and after three years in charge he helped them gain promotion once again to the top flight at the age of 36. During his time he helped the club establish themselves as a Primeira Liga club up until the 1993–94 season, when he left the club for Estrela da Amadora, and Estoril in that very season were relegated to the second tier.

After the departure of Fernando Santos as manager in 1994, the club was stuck around the Liga de Honra (D2). Since after the Liga de Honra's establishment the club participated in fourteen seasons in that division. In the 1998–99 Liga de Honra season, the club suffered relegation to the third tier of Portuguese football for the first time in their history. Then the club suffered several promotions and relegations.

At the beginning of the new millennium, the club was playing in the Portuguese Second Division. Ulisses Morais took over in 2002 and led the club to back to back promotions leading the club to the top flight. Litos took over for the 2004–05 Primeira Liga season where the club finished seventeenth and were relegated after one season.

In the 2011–12 season, the club was promoted to first division by winning the Liga de Honra five points ahead of second place Moreirense. With new owners and under the management of Marco Silva who halfway through the season took over from Vinícius Eutrópio, the team claimed the second Liga de Honra title in the club's history. The main players on the title roster were João Coimbra, Licá, Steven Vitória and Vagner. The 2012–13 season marked the return of the club to the Primeira Liga and saw them finish in an impressive fifth place in the league, from the position of newly promoted, and also qualify for the third qualifying round of Europa League, marking its first presence in the European competitions. Estoril reached Europa League group stages after defeating Hapoel Ramat Gan and Pasching. They finished fourth place in a group against Sevilla, Freiburg and Slovan Liberec, with only three points in three draws against Sevilla and Freiburg (twice). In the 2013–14 season, Estoril finished in fourth place, marking its best performance ever in the Portuguese first division, qualifying directly to Europa League's Group Stage.

American investor David Blitzer, through his company Global Football Holdings, purchased a majority stake in the club in May 2019.